The dark days of Venice continue. It’s not easy starting your morning with a film called “Black Souls” but someone has to do it. Italian director Francisco Munzi’s tale of a Calabrian family embroiled in the mafia gave me a stomach ache, partly because of the sense of dread it successfully exported from the opening shot, and partly because it never quite achieves what it seems to be going for.

Luigi and Rocco Carbone are two middle-aged brothers running a mob business in Milan. Luigi (Marco Leonardi) is your typically good-looking, fun-loving tough guy, a sort of Calabrian Sonny Corleone. The lean, bespectacled Rocco (Peppino Mazzotta) runs the business side and aspires to normality and respectability, with a pretty northern wife (Barbora Bobulova) and young daughter. The odd man out is their elder brother Luciano (Fabrizio Ferracane), who has remained on the Calabrian hilltop farm, raising goats, and out of the his brothers’ business. This despite, or perhaps because of, the fact that their father had been murdered by the other local crime family, the Barracas.

The trouble is, Luciano’s hard-one independence doesn’t appeal to his only son Leo (Giuseppe Fumo), who takes after Luigi and Rocco. Like many a mob personality before him, Leo’s never heard an insult that didn’t require response with a gun – in this case, simply shooting up the sign and windows of a bar affiliated with the Barracas. This sets into motion a series of further insults and events that require a meeting with another friendly family, discussion of the right form of revenge, threats and counter threats, betrayal. You know the stuff. What makes the film different, I guess, is its chiaroscuro treatment of an old-school mob world, the Calabrian countryside and dialect – the screening here featured subtitles in Italian as well as English – and its shocking denouement. But as interesting as the ending is, it’s also entirely unconvincing. And where do you go from there?

To the mean grey streets of Manhattan and Joshua and Ben Safdie’s “Heaven Knows What,” which is convincing as hell. That is in part because it is based on its star’s own life on the streets: The Safdies are said to have met then-19-year-old homeless addict Arielle Holmes while researching another project, and asking her to write up her story, which included an abusive relationship with a fellow street addict named Ilya. Later, when they decided to film it, they asked Holmes to play herself, which is, A, crazy, and, B, crazy good, because it and she work very well.

This is not to say that the time spent in Arielle/Harley’s world is even remotely pleasurable – it’s like being stuck in a very long Ryan Trecartin video, god help us – but she has an affecting, almost comforting presence even at her most depressing/annoying/desperate. And she can act – there’s not a moment that feels amateurish. The supporting cast is also fine, especially Caleb Landry Jones, who seems to channel Ilya rather than play him. It’s hard to think of a recent character I both despised and pitied so much.

There is no moral arc here or uplifting moment; we enter this jittery fractured world and gratefully leave it 94 minutes later. But it’s an interesting and memorable ride, with some good and very loud music, like one of those rides you got hitchhiking and wish you hadn’t except for that girl in the front seat whose eyes you can’t stop thinking about. No uplift, no, but later seeing Arielle Holmes walking down Lido’s Marconi strada with two of her co-stars, well, that’s some Hollywood ending.

There’s certainly no such ending to Veronika Franz and Severin Fiala’s “Ich Seh, Ich Seh (Goodnight Mommy).” We’ve already heard from Franz as the conceiver of her husband Ulrich Seidl’s kinky-kitshcy doc “In the Basement,” but “Mommy” goes several steps further. I’m beginning to think Franz and Seidl make their films in their basement. Indeed, the film starts off with a bit of weird Austrian kitsch – an actual clip of the Von Trapp Family Singers singing the goodnight song.

The film doesn’t sound like much on paper, which is no doubt purposeful: A woman returns home following cosmetic facial surgery, and her children don’t recognize her – even after she takes off the bandages. Those children happen to be twin pre-teen boys, and there is more to them than their beatific faces suggest. At the beginning we see them running through cornfields near their semi-rural home, playing hide-and-seek, going into dark places or under water to scare each other. Their mother, who is a television professional (thus, presumably, the surgery) and is separated or divorced from their father, does not return home a happy woman – it’s never clear why, actually — and treats the boys roughly. At first, they believe her just to be tired and stressed, but soon they begin to suspect that she isn’t their mother at all. Mama would never treat them like this.

Fiala and Franz don’t want us to be sure either, as far as that goes. At one point, the mother walks into the woods, takes off her clothes and goes into some weird David Lynchian trance. And what is at first tension between her and the boys soon turns into something else – a real struggle for control. Things get weirder and weirder as they try to force her to prove that she’s actually their mother. One of the film’s unpleasant manipulations is just how lame her attempts to prove it are, given the increasingly dire consequences and how easy it would be to come up with some detail that only she could know. Are we to believe she simply doesn’t understand, or take them seriously?

There are moments in the film when those consequences are extremely discomforting. I was tempted to walk out but in the end I was glad I stayed for a crucial last-minute surprise. It doesn’t make those scenes easier to watch but it does put them in perspective. Still, that may not be enough for many viewers; this isn’t for everyone and I’m not certain it should be for anyone. That said, “Goodnight Mommy” is an accomplished film, featuring lovely almost-still photography, effective production design, and some subtle-weird performance by Elias and Lukas Schwarz. I just don’t know that all of that is worth this little exercise in sadism. What exactly are Franz and Fiala trying to tell us? That beneath the surface of this beatific Von Trappish appearance lurks a real darkness? Mission accomplished but I think it’s been done.